You should not tighten up the tie-downs too tight. You can place too much stress on the campers anchors. It is possible to do damage to the camper that way. Its ok for the camper to move a little. Lance uses front cabover shocks to dampen the camper pitching.
http://forums.woodalls.com/index.cfm/fuseaction/thread/tid/23379570/print/true.cfm For general info. There are torlift videos on Youtube to show you how to adjust them for proper tensioning.
A rubber mat will keep the camper from sliding. I have seen a rubber mat, plywood for height and then another rubber mat on top of that OR use 2x2 interlocking foam flooring , less expensive and does the job.
other options: found in the projects section of the forum.
http://www.rv.net/forum/Index.cfm/fuseaction/thread/tid/16957495.cfmprojects section